Many European countries have experienced their warmest January temperatures ever.
In eight countries, national records have fallen, and regional records in three more.
On Sunday, Warsaw, Poland, recorded 18.9C (66F), while Bilbao, Spain, reached 25.1C, which is more than 10C above average.
The mild European weather comes days after a deadly winter cold snap that claimed more than 60 lives in North America.
Heavy snow and freezing rain have been forecast for parts of the northern Midwest while severe thunderstorms and tornadoes are expected in Texas, Oklahoma, Arkansas and Louisiana.
But on the European side of the Atlantic, the weather has been balmy for many places at the start of the year.
Temperatures in the Netherlands, Liechtenstein, Lithuania, Latvia, Czech Republic, Poland, Denmark and Belarus broke national records.
Station records were broken in Germany, France and Ukraine.
The temperature recorded in Warsaw on 1 January was 4C higher than the previous record for the month, and Belarus' record high was 16.4C, some 4.5C above the previous record.
In Spain, New Year's Day temperatures in Bilbao were equivalent to the average in July, and parts of Catalonia including Barcelona are subject to restrictions on water use.
Records are broken all the time, but it is unusual for the difference to be more than a few 10ths of a degree.
Temperatures reached 20C in Switzerland, and the warm weather has caused a snow shortage at ski resorts all over the Alps.
However, not all of Europe is experiencing warm weather. Parts of Scandinavia are predicted to experience colder temperatures and snow, and Moscow is predicted to experience a weekend low of -20C.
Only a few days earlier, 2022 was dubbed the hottest year on record by the UK, Ireland, France, and Spain.
Except for December, every month in the UK was warmer than usual. Although the weather is now milder and wetter, much of the country experienced snowfall in December.
Due to human-induced climate change, heat waves are now more frequent, more intense, and last longer.
However, compared to summer heat waves, which can cause numerous excess deaths, winter events like these do not have the same human impact.
Since the start of the industrial era, the world has already warmed by about 1.1C, and temperatures will continue to rise unless governments drastically reduce emissions.